Blog

Reproducible notes on software architecture: the papers behind the metrics, diagrams that explain them, and measurements from real codebases.

• August 3, 2026 · Architecture metric · 9 min read

  Code Hotspots: Where Complexity and Churn Meet

  I ranked large, frequently changed files from 18 months of history, then tested the shortlist against six months of later bug-fix activity.

• July 26, 2026 · Architecture metric · 16 min read

  Change Coupling: The Dependency Graph Only Git Can See

  Files that change together in commits are coupled whether or not they import each other: the co-change graph laid over the import graph for five JavaScript codebases.

• July 21, 2026 · Architecture metric · 12 min read

  Architecture Debt with an Actual Interest Rate

  Coupled file groups, their bug-fix cost per release, and the fitted curve that says whether a debt is accelerating: the ICSE 2016 method, approximated on five JavaScript codebases.

• July 12, 2026 · Architecture metric · 15 min read

  Decoupling Level: How Replaceable Is Your Codebase?

  The share of a system living in small, independently replaceable modules: the ICSE 2016 metric, approximated from the import graphs of eleven codebases.

• July 5, 2026 · Architecture metric · 9 min read

  Propagation Cost: The Number That Measured Mozilla's Rewrite

  One number for how far a change can ripple: the 2006 paper that measured Mozilla's redesign, and the same metric computed on eleven codebases today.

• June 28, 2026 · Practice · 6 min read

  Fitness Functions: Telling If Your Architecture Still Works

  Where the idea comes from, the problem it solves, a mental model drawn out, examples across seven industries, and an interactive quiz.

• June 21, 2026 · Architecture metric · 7 min read

  The Modularity Maturity Index

  Its history, its three pillars drawn out, and a demo library broken then fixed to show what each one costs.

• March 12, 2026 · Case study · 4 min read

  SaleSpotter: A Technical Retrospective

  Architecture, challenges, and lessons learned from building a large-scale retail data platform.